Validation of dimensionless method using height average wind velocity for wind forces

Abstract

The wind forces acting on a ship are normalized using the air density, the projected area of the ship and the representative wind velocity. In this regard, the authors have presented that the use of height average wind velocities (HAWV) can reduce the effect of differences in wind profiles on wind force coefficients. In this study, the results of wind forces calculations carried out by several companies and institutes using flow solvers available for each participant on two types of ships were compared, and show the effectiveness of HAWV. The CFD calculations were performed with different wind profiles depending on the participants of the calculation. Although the difference of calculation conditions of each simulation causes the difference of profiles of inflow velocity and the wind forces acting on the ship, the HAWV have been proposed as an appropriate, representative wind velocities for the normalization which can reduce the influence of the difference of the wind profiles by considering the concept of kinetic energy. The normalization with the HAWV provides flexibility in CFD calculation settings and in the same in modeling wind profile demanded for estimation of the wind forces. This approach also expands the possibilities of available CFD tools. In addition, the calculation results with various configurations, such as differences in boundary conditions set in computational domain, mesh types and considerations of flow unsteadiness, were non-dimensionalized by HAWV method with enough accuracy for practical use. It indicates that the above variations might be the options for the computation set up.